Using an arch to support a bridge is well known, and has been variously employed for hundreds of years. Until very recently, the bridge deck being supported by one or more arches has been substantially straight, at least for each section that is within the span of the arch. In some recent bridge designs, a horizontally (laterally) curved deck is suspended by suspension members (e.g., cables) extending down to it from an overhead arch that is more vertical than horizontal. In these prior art designs, the suspension members are necessarily angled with respect to portions of the deck because the arch is not directly above most of the deck's length. The more that the deck is curved, the more this affects the angle of the suspension members. Obviously cables that slant at a significant angle across the deck will interfere with persons and/or vehicles passing along the deck. Furthermore, instead of simply hanging from (vertical) suspension members attached to both sides of the deck, the deck is additionally given unbalanced lateral stress forces that cause tension, compression, bending, and/or torsion.
The prior art practice to resolve this problem includes, for example, some form of outrigger that laterally extends the deck's side, or for example, provides an intermediate structure around which the suspension members can wrap to change to a more nearly vertical orientation at the deck edge. These accommodations require extra strengthening structure in and around the deck, thereby increasing the complexity, bulk, and cost of the structure.
It is an object of the present invention to provide a method for supporting horizontally curved decks that doesn't require so much deck structure to handle.